The objectives of this study is to increase efficiency of steam boiler 2.5 ton per hour which used liquid petroleum gas LPG as fuel. bringing heat recovery inside boiler chimney stack to preheat feed water with technology heat Exchanger Economize. Taking the economizer with its pipe length of 1000 mm and 62 mm diameter for 64 pipe is a cross flow with staggered tube to increase water temperature before entering the boiler pass to deaerator The study is carried out to compare the differences and savings of the feed water temperature steam boiler efficiency and fuel consumption between having the economizer installed and uninstalled. reference to study The result after installed the heat exchanger economizer the feed water is passed into steam boiler deaerator higher temperature from 38.30°C to 67.20°C which leads to increase efficiency of steam boiler from 81.59 % to 85.65 % meaning that the fuel consumption of steam boiler will be reduced 4.97 %

The research objective is to utilize the waste water at 12ºC to 20ºC in exchange with the process water at the temperature of 29ºC. After entering the heat exchanger the process water will have the reduced temperature of 19ºC and then will be delivered to the cooler so the temperature of the process water will further be reduced to 15ºC to involve in the production process. Consequently the cooler’s energy use is lower. Since the common coolers used in these days have problems about the clogged system caused by shrimp residue the cleanup of the system is difficult and the maintenance cost is high. With this problem the research and development of the new heat exchanger is carried out resulting to the Shell and Tube Heat Exchanger type with the angled lid and the waste water flow control pads allowing the water alternatingly running through the lower part and upper part of each pad. The process water will flow in the 6 sets of the stainless tubes with 2 mm. thickness ½ inch diameter and 6 meter length. The space between the set is 5 centimeters for exchanging heat with the waste water flowing outside the tubes. The study conclusion is that the new heat exchanger can reduce the temperature of the process water to 19ºC so it can save the electricity cost of the cooler for 886485 baht per year and make the cleanup easier without taking off the equipment parts thus lowering the maintenance cost as well.

The aim of this study was to develop a three-dimensional transient condition model to predict the heat transfer rate of a heat pipe heat exchanger. This paper presents the details of the calculated domains which consist of the wall wick and vapor core. They were numerically simulated using the finite element method. The heat transfer rate values obtained from the model simulation can be used to design heat pipe heat exchangers. The values obtained from the model calculation were then compared with the results from experiments and the differences were 10.3% 10.4% and 6.7% for the working fluids of distilled water ethanol and R134a respectively. The working fluids of distilled water ethanol and R134a obtained heat transfer rates of 627.3 watts 522.8 watts and 836.4 watts from the experiments respectively.

This paper presents a study of heat exchanger design for improving the performance of ice maker by using waste water from ice factory. The heat exchanger was made of stainless steel and had 4.023 m2 of heating surface. After using the heat exchange in the waste water pond which the temperature was 0 C the temperature of feed water was decreased from 28 C to 22 C. The COP of the ice maker was increased and the factory can save energy consumption 52034 kWh/year or 61993 baht/year. The payback period was 0.5 year